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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

39258 results found.

  1. GRB 251222A: Fermi GBM Observation
  2. EP251220a: CrAO ZTSh optical observations
  3. EP251221a: PRIME upper limit
  4. EP251222a: Global MASTER-Net observations report
  5. GRB 251222A / EP251222b: GECAM-B observation
  6. EP251222b/GRB 251222A: refined analysis of the EP-WXT and EP-FXT observations
  7. Konus-Wind detection of GRB 251222A / EP251222b
  8. GRB 251222A: Swift-XRT afterglow detection
  9. GRB 251222A / EP251222b: LCO detection of the optical counterpart
  10. GRB 251222A / EP251222b: GOTO optical counterpart detection
  11. GRB 251222A / EP251222b: LCO optical observations
  12. GRB 251222A: 1.3m DFOT optical detection
  13. GRB251221A: 7DT optical upper limits
  14. GRB 251222A / EP251222b: VLT/X-shooter spectroscopic redshift z = 3.171
  15. GRB 251222A / EP251222b: SVOM/VT optical rebrightening
  16. EP251222b/GRB 251222A: SVOM/GRM observation
  17. EP251222b/GRB 251222A: Einstein Probe detection of an X-ray transient
  18. EP251221a: Global MASTER-Net observations report
  19. GRB 251222A: PRIME near-infrared detection
  20. GRB 251222A: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  21. GRB 251222A: NOT optical observations
  22. IPN triangulation of GRB 251220B (short)
  23. GRB 251222A: Swift ToO observations
  24. GRB 251222A: BALROG localization (Fermi Trigger / GRB 251222712)
  25. GRB 251222A: SVOM/VT optical candidate
  26. GRB 251222A: SVOM detection of a long burst
  27. SVOM GRB251222A: Global MASTER-Net observations report
  28. GRB 251222A: Fermi GBM Final Real-time Localization
  29. EP251220a: PRIME upper limit
  30. GRB 251221A: PRIME near-infrared observation
  31. GRB 251221A: UAFO and Mondy optical upper limit
  32. GRB 251221A: Swift-XRT refined Analysis
  33. GRB 251221A: Swift/UVOT Upper Limits
  34. Fermi Gamma-ray Burst Monitor trigger 788028118/251221696 is not a GRB
  35. GRB 251221A: Enhanced Swift-XRT position
  36. GRB 251221A: Fermi GBM Observation
  37. GRB 251221B: Fermi GBM Final Real-time Localization
  38. GRB 251220B: SVOM/GRM observation of a short burst
  39. EP251220a: COLIBRÍ confirmation of fading and photometric redshift upper limit of z < 3.4
  40. GRB 251221A: COLIBRÍ detection of the optical counterpart
  41. EP 251220a: COLIBRÍ detection of the optical counterpart
  42. GRB 251221A: Swift detection of a burst
  43. Swift GRB251221A: Global MASTER-Net observations report
  44. GRB 251221A: Fermi GBM Final Real-time Localization
  45. EP251220a: Global MASTER-Net observations report
  46. SVOM GRB251220.98: Global MASTER-Net observations report
  47. GRB 251220B: Fermi GBM Final Real-time Localization
  48. GRB 251219A: SVOM/GRM observation of a short burst
  49. GRB 251219A: GECAM-B detection of a possible magnetar X-ray burst from SGR 1830-0645
  50. Fermi-LAT Gamma-ray Observations of IceCube-251218A
  51. GRB 251220A: MAXI/GSC detection
  52. GRB 251215A: Swift-XRT afterglow detection
  53. IceCube-251218A: COLIBRÍ optical upper limits
  54. SVOM GRB251219.11: Global MASTER-Net observations report
  55. IceCube Alert 251218.85: Global MASTER-Net observations report
  56. GRB 251214B: VIRT Optical Upper Limit
  57. Fermi trigger No 787736968: Global MASTER-Net observations report
  58. Fermi GRB 251217A: Global MASTER-Net observations report
  59. GRB 251217A: Fermi GBM Final Real-time Localization
  60. GRB 251215A: Swift/UVOT Upper LImits
  61. GRB 251215A: Fermi GBM Observation
  62. Fermi GRB 251216A: Global MASTER-Net observations report
  63. GRB 251202A/EP251202a: Koshka optical upper limit
  64. GRB 251214B: Mondy optical upper limit
  65. GRB 251215A: COLIBRÍ optical upper limit
  66. GRB 251216A: Fermi GBM Final Real-time Localization
  67. EP251214b: KAIT optical upper limit
  68. GRB 251215A: Swift-XRT observations
  69. Fermi GRB 251215A: Global MASTER-Net observations report
  70. GRB 251214B: 1.6m Mephisto observations with newly installed mosaic cameras
  71. GRB 251215A: Glowbug gamma-ray detection
  72. GRB 251214B: UAFO optical upper limit
  73. GRB 251214B: VLT/X-shooter observations
  74. GRB 251213A: GRID-10B observation
  75. GRB 251214B: Swift-BAT refined analysis
  76. GRB 251202A: radio detection with the VLA
  77. EP251214b: Global MASTER-Net observations report
  78. GRB 251214B: AbAO optical observations
  79. GRB 251214B: LCO detection of the optical counterpart
  80. GRB 251209A: GECAM-B observation of a long burst
  81. GRB 251214D: GECAM-B observation of a long burst
  82. GRB 251214B: Fermi GBM Observation
  83. GRB 251209A: Insight-HXMT/HE detection
  84. GRB 251215A: Swift ToO observations
  85. GRID detection of GRB 251213A
  86. GRB 251203B: AbAO optical observations
  87. GRB 251215A: Swift/BAT-GUANO arcminute localization of a burst
  88. GRB 251214B: GECAM-B observation of a long burst
  89. GRB 251214B: Swift-XRT refined Analysis
  90. GRB 251213A: SVOM/GRM observation
  91. EP251214a: KAIT optical upper limit
  92. GRB 251214D: AstroSat CZTI detection of a long burst
  93. GRB 251213A: AstroSat CZTI detection
  94. GRB 251214A: AstroSat CZTI detection
  95. GRB 251213A: GECAM-B detection
  96. GRB 251214B: Swift/UVOT Detection
  97. GRB 251215A: Fermi GBM Final Real-time Localization
  98. GRB 251214B: COLIBRÍ observations of the afterglow
  99. GRB 251214A: GECAM-B observation of a likely long burst
  100. GRB 251214B: 1.3m DFOT optical detection

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